United states securities and exchange commission

Table of Contents
68
Milestone and Upfront Expenses included in 
Research and Development Expense
Research and development expense for 2017 
includes:
•  $300.0 million upfront payment made to BMS 
upon entering into our agreement to exclusively 
license BIIB092;
•  $60.0 million developmental milestone 
payment due to the former shareholders of 
iPierian, Inc. (iPierian), which became payable 
upon dosing of the first patient in the Phase 2 
PSP study for BIIB092;
•  $28.0 million upfront payment made to 
Alkermes upon entering into our agreement to 
exclusively license BIIB098, representing our 
share of BIIB098 development costs already 
incurred in 2017;
•  $50.0 million accrual based upon the expected 
continuation of our agreement with Alkermes to 
develop and exclusively license BIIB098; and
•  $25.0 million upfront payment recognized upon 
entering into a new collaboration agreement 
with Ionis to identify new ASO drug candidates 
for the treatment of SMA. 
Research and development expense for 2016 
includes:
•  $75.0 million license fee paid to Ionis as we 
exercised our option to develop and 
commercialize SPINRAZA from Ionis;
•  $50.0 million milestone payment to Eisai 
related to the initiation of a Phase 3 trial for 
E2609; and 
•  $20.0 million upfront payment recognized upon 
entering into a collaboration and alliance 
agreement with UPenn. 
Research and development expense for 2015 
includes:
•  $60.0 million recognized upon entering into our 
collaboration with Mitsubishi Tanabe Pharma 
Corporation;
•  $48.1 million recognized upon entering into our 
collaboration with AGTC;
•  $30.0 million in milestones recognized in 
relation to our collaboration agreements with 
Ionis; and 
•  $16.0 million paid to AbbVie related to 
milestones for the development of ZINBRYTA as 
a result of filing with the FDA and EMA during 
2015. 
These payments are classified as research and 
development expense as the programs they relate to 
had not achieved regulatory approval as of the 
payment date.
For additional information about these 
collaborations, please read Note 20, Collaborative and 
Other Relationships, to our consolidated financial 
statements included in this report.
Early Stage Programs
The increase in spending associated with our 
early stage programs for 2017 compared to 2016 
was primarily related to spending associated with the 
development of BIIB092 in AD and PSP pursuant to 
our license agreement with BMS, BIIB074 in 
trigeminal neuralgia (TGN) and BIIB076 in AD. These 
increases were partially offset by a reduction in costs 
resulting from our discontinuance of development of 
amiselimod in the third quarter of 2016.
The decrease in spending associated with our 
early stage programs for 2016 compared to 2015 
was primarily due to the advancement of our 
aducanumab program in AD to a late stage program in 
the third quarter of 2015, decreased costs incurred in 
connection with opicinumab in MS and the 
discontinuance of development of anti-TWEAK in lupus 
nephritis. These decreases were partially offset by 
increased costs of BIIB074 in TGN and increased 
costs associated with our discontinuance of 
development of amiselimod in the third quarter of 
2016.
Late Stage Programs
The increase in spending associated with our 
late stage programs for 2017 compared to 2016 was 
primarily related the increased costs associated with 
the development of aducanumab in AD and costs 
incurred associated with the development of E2609, a 
BACE inhibitor that was advanced to a late stage 
program in the fourth quarter of 2016. These 
increases were partially offset by advancement of 
SPINRAZA to marketed products following its approval 
in the U.S. in the fourth quarter of 2016.
The increase in spending associated with our 
late stage programs for 2016 compared to 2015 was 
primarily driven by costs incurred to advance our 
aducanumab program in AD, the increased costs 
incurred to advance our SPINRAZA program and the 
advancement of E2609 to a late stage program in the 
fourth quarter of 2016, partially offset by the approval 
of ZINBRYTA in the third quarter of 2016.

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Table of Contents
69
Marketed Products
The decrease in spending associated with our 
marketed products for 2017 compared to 2016 was 
primarily due to a reduction in spending resulting from 
the spin-off of our hemophilia business on February 1, 
2017 and a reduction in spending related to 
TECFIDERA. These decreases were partially offset by 
increased spending related to SPINRAZA following its 
approval in the U.S. in the fourth quarter of 2016. 
The decrease in spending associated with our 
marketed products for 2016 compared to 2015 was 
primarily due to the discontinuance of development of 
TYSABRI and TECFIDERA in secondary primary MS in 
the third and fourth quarters of 2015, respectively, 
and decreased costs incurred in connection with our 
hemophilia products. These decreases were partially 
offset by the approvals of ZINBRYTA and SPINRAZA in 
the third and fourth quarters of 2016, respectively. 
Selling, General and Administrative
For 2017 compared to 2016, the decrease in 
selling, general and administrative expenses was 
primarily due to a reduction in operational spending 
resulting from the spin-off of our hemophilia business 
on February 1, 2017, the execution of targeted cost 
reduction initiatives and a reduction in costs resulting 
from the discontinuance of our TECFIDERA television 
advertising campaign in the second quarter of 2016. 
These decreases were offset by an increase in 
SPINRAZA commercialization costs and an increase in 
corporate giving.
For 2016 compared to 2015, the decrease in 
selling, general and administrative expenses reflect 
cost savings in connection with our corporate 
restructuring, which are described below under the 
heading "Restructuring, Business Transformation and 
Other Cost Savings Initiatives," partially offset by an 
increase in costs associated with developing 
commercial capabilities for ZINBRYTA and SPINRAZA.  
Amortization of Acquired Intangible Assets
Our amortization expense is based on the 
economic consumption and impairment of intangible 
assets. Our most significant intangible assets are 
related to our TECFIDERA, AVONEX and TYSABRI 
products. Annually, during our long-range planning 
cycle, we perform an analysis of anticipated lifetime 
revenues of TECFIDERA, AVONEX and TYSABRI. This 
analysis is also updated whenever events or changes 
in circumstances would significantly affect the 
anticipated lifetime revenues of any of these 
products.
Our most recent long-range planning cycle was 
completed in the third quarter of 2017. The results of 
our TECFIDERA, AVONEX and TYSABRI analyses were 
impacted by changes in the estimated timing of the 
impact of other alternative MS formulations, including 
OCREVUS, which may compete with TYSABRI, 
TECFIDERA and AVONEX. The outcome of this most 
recent analysis did not result in a significant net 
change in our expected rate of amortization for 
acquired intangible assets. 
Based upon this most recent analysis, the 
estimated future amortization of acquired intangible 
assets for the next five years is expected to be as 
follows:
(In millions)
As of December 31,
2017
2018
$
423.5
2019
401.8
2020
381.6
2021
254.3
2022
242.3

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